가열에 의한 한우유의 유청단백질의 변화

김영교,염창훈 한국낙농학회 1991 韓國酪農學會誌 Vol.13 No.3

본 실험은 가열에 의한 한우유의 유청단백질의 변화를 조사하기 위하여 실행되었다. 열변성된 유청단백질의 물리화학적 성질을 알아보기 위하여 전기영동에 의한 유청단백질의 밴드의 변화를 조사하였고, 초원심분리에 의한 침전물을 측정하였다. 실험결과를 종합하여 요약해보면 다음과 같다. 1. 65℃에서 30분, 75℃에서 20분, 85℃에서 10분, 95℃에서 5분동안 가열처리한 한우유의 유청단백질의 전기영동상의 형태는 가열하지 않은 유청단백질의 전기영동상의 형태보다 각각의 밴드의 모양이 흐려지는 것을 볼 수 있다. 2. 65℃에서 39분, 75℃에서 20분, 85℃에서 10분, 95℃에서 5분동안 가열처리한 한우의 탈지유의 전기영동상의 형태는 가열하지 않은 탈지유의 전기영동상의 형태보다 각각의 밴드의 모양이 흐려지는 것을 볼 수 있다. 3. 동일한 온도에서 한우유의 유청단백질의 변성도는 가열시간이 길어질수록 각각 증가하는 것으로 나타났다. 4. 동일한 온도에서 한우의 탈지유의 변성도는 가열시간이 길어질수록 각각 증가하는 것으로 나타났다. This experiment was conducted to examine heated-indued change of whey protein of Korean native cattle`s milk by heat treatment. In order to study some physico-chemical properties of the heat-denatured whey protein the change of electrophoretic bands was observed, and denaturation of the whey protein heated at various temperature was measured by means of ultracentrifugation. The results obtained were summarized as follow: 1. When the whey protein alone isolated from Korean native cattle`s milk was heated at 65℃ for 30min, 75℃ for 20min, 85℃ for 10min, and 95℃ for 5min, respectively, the electrophoretic bands of whey protein were dispersed and the densities of them were decreased as compared with those of the whey protein not heated. The dispersion of the bands was increased with the higher and the longer heat treatment. 2. When the skimmilk was heated at the various temperature for the fixed time, the densities of electrophoretic bands of the whey protein were decreased as well as those of the isolated whey proteins. 3. When the isolated whey protein and the skimmkilk were heated respectively under the same conditions, heat denaturation of them showed a similar tendency, but the degree of denaturation of the isolated whey protein was higher than that of the skimmilk.

Pure Cobalt Thin Film by using Very High frequency (60MHz) Plasma-Enhanced Atomic Layer Deposition

Chang Hoon Song,Won Kyun Yeom,Doo San Kim,Won Oh Lee,Soo jung Lee,Geun Young Yeom 한국진공학회 2018 한국진공학회 학술발표회초록집 Vol.2018 No.8

O₃/BAC 공정에서 Peroxone 공정 적용에 따른 잔류 과산화수소 제거 특성

염훈식(Hoon Sik Yeom),손희종(Hee Jong Son),서창동(Chang Dong Seo),김상구(Sang Goo Kim),류동춘(Dong Choon Ryu) 大韓環境工學會 2013 대한환경공학회지 Vol.35 No.12

수중의 미량 유해물질 제거를 위해 AOP 공정에 대한 관심이 증대되고 있다. 낙동강 하류에 위치한 정수장들은 대부분 O₃/BAC 공정을 채택하여 운전 중에 있으며, AOP 공정의 일종인 peroxone 공정의 적용에 많은 관심을 가지고 있다. 본 연구 에서는 O₃/BAC 공정을 운전 중인 정수장에서 과산화수소를 투입할 경우에 후단의 BAC 공정에서의 잔류 과산화수소의 제거 특성을 biofiltration 공정과 함께 평가하였다. 유입수의 수온 및 과산화수소 농도변화 실험에서 biofilteration 공정은 낮은 수온 에서 유입수 중의 과산화수소 농도가 증가하면 급격히 생물분해능이 저하된 반면, BAC 공정에서는 비교적 안정적인 효율을 유지하였다. 유입수의 수온을 20℃, 과산화수소 투입농도를 300 mg/L로 고정하여 78시간 동안 연속으로 투입한 실험에서 biofilteration 공정은 EBCT 5~15분의 경우 운전 24~71시간 후에는 유입된 과산화수소가 거의 제거되지 않았으나, BAC 공정 에서는 78시간 후의 과산화수소 제거율이 EBCT 5~15분일 때 38%~91%로 나타났다. 또한, 78시간 동안 연속 투입실험 후의 biofilter와 BAC 부착 박테리아들의 생체량과 활성도는 각각 6.0 × 104 CFU/g과 0.54 mg?C/m3?hr 및 0.4 × 108 CFU/g과 1.42 mg?C/m3?hr로 나타나 운전초기에 비해 biofilter에서는 생체량과 활성도가 각각 99%와 72% 감소하였으며, BAC의 경우는 각 각 68%와 53%의 감소율을 나타내었다. BAC 공정에서 생물분해 속도상수(kbio)와 반감기(t1/2)를 조사한 결과, 수온 5℃에서 과산화수소 농도가 10 mg/L에서 300 mg/L로 증가할수록 kbio는 1.173 min-1에서 0.183 min-1으로 감소하였고, t1/2은 0.591 min 에서 3.787 min으로 증가하였다. 수온 25℃의 경우 kbio와 t1/2은 1.510 min-1에서 0.498 min-1 및 0.459 min에서 1.392 min으로 나타나 수온 5℃에 비해 수온이 15℃와 25℃로 상승할 경우 kbio는 각각 1.1배~2.1배 및 1,3배~4.4배 정도 증가하였다. O₃/BAC 공정을 운전 중인 정수장에서 peroxone 공정의 적용을 위해 과산화수소 투입을 고려할 경우, 후단의 BAC 공정에서 잔류 과 산화수소를 효과적으로 제거 가능하였고, 고농도의 과산화수소 유출사고시에는 BAC 공정의 EBCT를 최대한 증가시켜 운전 할 경우 수중의 과산화수소 농도를 최대한 저감시킬 수 있을 것으로 판단된다. Advanced Oxidation Processes (AOP) have been interested for removing micropollutants in water. Most of water treatment plants (WTPs) located along the lower part of Nakdong River have adopted the O₃/BAC process and have interesting in peroxone process a kind of AOP. This study evaluated the removal characteristics of residual hydrogen peroxide (H₂O₂) combining with the biofiltration process in the next BAC process when the hydrogen peroxide is applied for the WTP operating O₃/BAC process. In the experiment, changing the temperature and the concentration of H₂O₂ of influent, the biofiltration process showed rapidly dropped the biodegradability when the H₂O₂ concentration was increased and lowered water temperature while BAC process maintained relatively stable efficiency. The influent fixed at 20℃ and the concentration of H₂O₂ at 300 mg/L was continuously input for 78 hours. Most of the H₂O₂ in the influent did not remove at the biofiltration process controlled 5 to 15 minutes EBCT condition after 24~71 hours operating time while BAC process controlled 5 to 15 minutes EBCT showed 38~91% removal efficiency condition after 78 hours operating time. Besides, after 78 hours continuously input experiment, the biomass and activity of attached bacterial on the biofilter and BAC were 6.0 × 104 CFU/g, 0.54 mg·C/m3·hr and 0.4 × 108 CFU/g, 1.42 mg·C/m3·hr respectively. These biomass and activity values were decreased 99% and 72% in biofilter and 68% and 53% in BAC compared with initial condition. The biodegradation rate constant (kbio) and half-life (t1/2) in BAC were decreased from 1.173 min-1 to 0.183 min-1 and 0.591 min to 3.787 min respectively according to increasing the H₂O₂ concentration from 10 mg/L to 300 mg/L at 5℃ water temperature and the kbio and t1/2 were 1.510 min-1 to 0.498 min-1 and 0.459 min to 1.392 min at 25℃ water temperature. By increasing the water temperature from 5℃ to 15℃ or 25℃, the kbio were increased 1.1~2.1 times and 1.3~4.4 times. If a water treatment plant operating O₃/BAC process is considering the hydrogen peroxide for the peroxone process, post BAC could effectively decrease the residual H₂O₂, moreover, in case of spilling the H₂O₂ into the water process line, these spilled H₂O₂ concentration can be able to decrease by increasing the EBCT at the BAC process.

High Redshift Simulations using the GALEX Ultraviolet Images of Nearby Galaxies

Yeom, Bum-Suk,Kim, Young-Kwang,Rey, Soo-Chang,Joe, Young-Hoon,Paz, Armando Gil de 한국우주과학회 2008 한국우주과학회보 Vol.17 No.1

Electrical Properties of BiFeO3 Doped PZT Thin Films for Embedded FeRAM Devices

Chang Young Koo,Chang Young Koo,Jong-Hyeon Cheon,하조웅,Jung-Hoon Yeom,김승현,Suk-kyoung Hong 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.III

For realization of reliable embedded FeRAM devices, it is necessary to prepare high-quality ferroelectric capacitors and to enhance their properties to give high remnant polarization, low leakage current density and good imprint and retention characteristics in ferroelectric capacitors with very small film thickness, but it is difficult to obtain such ideal ferroelectric thin films. To obtain high-quality ferroelectric capacitors, we adopted BiFeO3 as a dopant in PZT thin films and investigated the ferroelectric performance of BiFeO3-doped PZT thin films with 100-nm film thickness. It was observed that highly (111) oriented BiFeO3-doped PZT thin films annealed at 600 C showed sharp and rectangular hysteresis loops with high remanent polarization values, even at a low applied voltage of 2 V (30 μC/cm2 at 2 V). To evaluate the long-term stability of BiFeO3 doped PZT thin films, the imprint behavior due to a thermal stress condition under a remanence bias and the opposite state retention by a heat-induced method were investigated. The BiFeO3- doped PZT thin films showed stable imprint endurance (V : 0.44 after 10000 seconds) and good retention characteristics (over 65 % retained charge after 100 hours). From the results, it was clarified that BiFeO3 dopant into the PZT thin film could be successfully applied to FeRAM devices with enhanced ferroelectric performance and provided the possibility of realizing future embedded FeRAM devices.

HVDC 케이블 접속제용, EPDM/Nano SiC 콤포지트의 전기전도도 및 공간저하 거동에 관한 특성

송창훈(Chang-Hun Song),신현우(Hyeon-Woo Shin),안동훈(Dong-Hoon An),양지상(Ji-Sang Yang),염철훈(Chul-Hoon Yeom),오진환(Jin-Hwan Oh),원태후(Tae-Ho Won),이지희(Ji-Hee Lee),이보인(Bo-In Lee),박재준(Jae-Jun Park) 대한전기학회 2020 대한전기학회 학술대회 논문집 Vol.2020 No.11

Scaling Issues of Pb(Zr, Ti)O$_3$ Capacitor Stack for High Density FeRAM Devices

김승현,Chang Young Koo,황철성,이동수,Dong-Yeon Park,Jieun Lim,하조웅,Jung-Hoon Yeom 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.IV

For realization of 32 Mb high density FRAM devices, the low stack height of capacitor from 750 nm to 300 nm should be accomplished with the scaling of thickness of PZT thin lms and electrodes below 100 nm. Otherwise, it is not possible of each capacitor to retain sucient distance with adjacent capacitors due to the diculty in obtaining steep etching slope of the capacitor, and which induces a critical device failure. To address these issues we explore the ferroelectric performance of the thickness scaled PZT thin lms (35 70 nm) on ultra thin bottom Pt electrodes (30 nm). It is observed that the switching performance of the thickness scaled PZT thin lms on sub-50 nm thick Pt bottom electrodes showed 1 V operation with sharp and rectangular hysteresis loops and high remanent polarization values (30 35 C/cm2), implying the possibility to realize 32 Mb FRAM devices and beyond. For a long-term stability of the capacitors, the lm thicknessdependent imprinting behavior was evaluated by a thermal stress process under a remanence bias. It is found that the voltage shift, which was attributed to the accumulation of charged defects near the electrode interface, increased linearly with increasing the lm thickness.

Bloodstream Infections and Clinical Significance of Healthcare-associated Bacteremia: A Multicenter Surveillance Study in Korean Hospitals

Son, Jun Seong,Song, Jae-Hoon,Ko, Kwan Soo,Yeom, Joon Sup,Ki, Hyun Kyun,Kim, Shin-Woo,Chang, Hyun-Ha,Ryu, Seong Yeol,Kim, Yeon-Sook,Jung, Sook-In,Shin, Sang Yop,Oh, Hee Bok,Lee, Yeong Seon,Chung, Doo The Korean Academy of Medical Sciences 2010 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.25 No.7

<P>Recent changes in healthcare systems have changed the epidemiologic paradigms in many infectious fields including bloodstream infection (BSI). We compared clinical characteristics of community-acquired (CA), hospital-acquired (HA), and healthcare-associated (HCA) BSI. We performed a prospective nationwide multicenter surveillance study from 9 university hospitals in Korea. Total 1,605 blood isolates were collected from 2006 to 2007, and 1,144 isolates were considered true pathogens. HA-BSI accounted for 48.8%, CA-BSI for 33.2%, and HCA-BSI for 18.0%. HA-BSI and HCA-BSI were more likely to have severe comorbidities. <I>Escherichia coli</I> was the most common isolate in CA-BSI (47.1%) and HCA-BSI (27.2%). In contrast, <I>Staphylococcus aureus</I> (15.2%), coagulase-negative <I>Staphylococcus</I> (15.1%) were the common isolates in HA-BSI. The rate of appropriate empiric antimicrobial therapy was the highest in CA-BSI (89.0%) followed by HCA-BSI (76.4%), and HA-BSI (75.0%). The 30-day mortality rate was the highest in HA-BSI (23.0%) followed by HCA-BSI (18.4%), and CA-BSI (10.2%). High Pitt score and inappropriate empirical antibiotic therapy were the independent risk factors for mortality by multivariate analysis. In conclusion, the present data suggest that clinical features, outcome, and microbiologic features of causative pathogens vary by origin of BSI. Especially, HCA-BSI shows unique clinical characteristics, which should be considered a distinct category for more appropriate antibiotic treatment.</P>

건식 탄화에 따른 왕겨의 이화학적 특성

이창훈(Chang-Hoon Lee),고병구(Byong-Gu Ko),염경래(Rai-Kyung Yeom),오택근(Taek-Keun Oh) 한국토양비료학회 2016 한국토양비료학회 학술발표회 초록집 Vol.2016 No.3

Electromechanical Properties of Pb(Zr, Ti)O$_3$ Films for MEMS Applications

김승현,Chang Young Koo,황철성,이동수,양정승,하조웅,Jung-Hoon Yeom,Kyu-Ho Hwang 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.IV

A systematic investigation of the piezoelectric and ferroelectric properties of PZT lms prepared by chemical solution deposition is performed for tetragonal (Zr/Ti = 30/70), morphotropic (52/48), and rhombohedral (70/30) composition. An atomic force microscope (AFM) is used to measure the magnitude of the eective longitudinal piezoelectric coecient (d33) of these lms. All lms are consistently highly textured (111) orientation and have dense microstructures. Slightly less degree of texture in higher Zr-rich composition is observed due to the lattice mismatch between PZT and Pt bottom electrode and higher activation energy for nucleation. Squareness of polarization hysteresis loops is optimized in tetragonal composition, which indicates the tetragonal PZT is closer to the ideal hysteresis behavior than other composition. It is shown that the piezoelectric coecient is dependent on the dielectric constant. The morphotropic PZT lms with 1 m thickness show the largest piezoelectric coecient values, which are comparable with those of bulk materials.